Combustion engines, and particularly engines for automotive use, have been the subject of considerable recent research. In that regard, reasonably good conventional engines are available and vast machinery exists for the economical production of such engines. However, it appears that conventional engines are approaching the stage of having been engineered to their limits with respect to minimizing fuel consumption and pollution along with the secondary considerations of noise, weight, and cost. As a consequence, the need for a substantially new engine has been recognized; however, the systems proposed to date apparently have not represented sufficient improvement to motivate the required substantial changes for meaningful production.
One type of developed engine that appears to offer substantial advantage operates on a resonant cycle as disclosed, for example, in U.S. Pat. Nos. 3,766,399; 3,805,083; and 3,848,415 all granted to the inventor named herein. Generally, resonant engines are piston internal-combustion devices which operate with all parts moving in a rectilinear, mechanically-resonant motion pattern. Energy is stored in the resonant mechanical system (rather than in a flywheel) and may be extracted variously as by an electric generator or a hydraulic system, as disclosed in the above-referenced patents. Also as disclosed therein, combustion cycles occur selectively to maintain resonant operation of the engine as during periods of idling, and to supply power demands during drive operation. Resonant engines and related structures as disclosed in the above-referenced patents as well as pending applications Ser. No. 375,374 (July 2, 1973) and Ser. No. 413,070 (Nov. 5, 1973) and further in accordance with the developments of the present invention offer substantial advantages with respect to various current considerations as will now be specifically treated.
In considering the importance of various characteristics for combustion engines, fuel consumption (efficiency) must be rated as very significant. Conventional internal-combustion engines (Otto cycle) which are in widespread use are quite inefficient, particularly both with respect to combustion and expansion during operation at high and low levels of power output. Although stratified charge engines and Diesel engines are capable of improved efficiency, the lateral forces inherent in such engines as they are conventionally constructed result in high frictional losses to limit the efficiency of operation. Contrasting these considerations relating to conventional engines, the resonant engine as embodied in the present system operates at a substantially constant frequency with the consequence that the engine can be optimized as an element of the design. Additionally, due to solely rectilinear motion patterns, the engine hereof does not involve lateral forces and as a consequence it is capable of operation with a substantially reduced friction load. As another characteristic relating to fuel economy, the engine as embodied in the present system burns fuel only during active combustion cycles which are initiated only when required either to maintain operation of the engine or to supply current demands for power. As a final consideration relating to fuel economy, the present system incorporates dynamic braking to further conserve energy and fuel.
The volume of pollutants that are produced by a combustion engine is another very important factor in evaluating engines for further widespread use. In that regard, it is initially noteworthy that improved engine efficiency results in the consumption of less fuel and an attendant proportionate reduction in the volume of the products of combustion, which may or may not include serious or harmful environmental pollutants. In any event, with respect to any particular form of engine, or system, the less fuel consumed, the less will be the quantity of pollutants that are contributed to contaminate the environment.
Further with regard to environmental polluting emissions, the system of the present invention may be designed for optimum resonant operation to obtain substantially consistent correct combustion. The system may be further improved in that regard by operating a Diesel cycle so as to produce relatively few serious pollutants. As a related matter, the relatively large size and weight of conventional Diesel engines may be avoided in systems of the present invention as a result of the sinusoidal linear motion patterns which are free of the lateral stresses that necessitate the heavy structures characteristic of conventional Diesel engines.
Another important aspect of the motive system of the present invention involves a considerable improvement over conventional Diesel engines in acceleration capability. This is, in accordance with the present system, acceleration may involve little change in the momentum of the resonant engine; and additionally effective control of combustion patterns permits a transition from minimum power output to maximum power output during the period of a single cycle of the engine.
In addition to the various aspects of engine performance, as treated above, another very important criterion concerns the cost required to obtain the production of engines in substantial numbers. In that regard, structural simplicity is an obvious benefit. Another distinct consideration is the degree to which an engine may utilize conventional components, e.g. pistons, valves, cooling apparatus and so on. Still another aspect relates to the requirements of the engine for ancillary apparatus, e.g. exhaust devices for pollutant control, noise control apparatus, or special equipment as the fuel injection pumps for certain forms of Diesel engines. The system of the present invention represents a substantial improvement with respect to these considerations.
In general, the present invention integrates a resonant, multiple-phase combustion engine having hydraulic output, with a dynamic valving unit for the cooperative operation of one or more hydraulic motors. The system further integrates control apparatus to vary the mechanical output, which includes negative drive power, i.e. braking, during which operation the kinetic energy of the driven system, e.g. automobile, supplies power through the hydraulic motor and the dynamic valve to be stored by the resonant engine.